Three‐Phase‐Heterojunction Cu/Cu₂O–Sb₂O₃ Catalyst Enables Efficient CO₂ Electroreduction to CO and High‐Performance Aqueous Zn–CO₂ Battery

Zn–CO 2 batteries are excellent candidates for both electrical energy output and CO 2 utilization, whereas the main challenge is to design electrocatalysts for electrocatalytic CO 2 reduction reactions with high selectivity and low cost. Herein, the three‐phase heterojunction Cu‐based electrocatalyst (Cu/Cu 2 O‐Sb 2 O 3 ‐15) is synthesized and evaluated for highly selective CO 2 reduction to CO, which shows the highest faradaic efficiency of 96.3% at −1.3 V versus reversible hydrogen electrode, exceeding the previously reported best values for Cu‐based materials. In situ spectroscopy and theoretical analysis indicate that the Sb incorporation into the three‐phase heterojunction Cu/Cu 2 O‐Sb 2 O 3 ‐15 nanomaterial promotes the formation of key * COOH intermediates compared with the normal Cu/Cu 2 O composites. Furthermore, the rechargeable aqueous Zn–CO 2 battery assembled with Cu/Cu 2 O‐Sb 2 O 3 ‐15 as the cathode harvests a peak power density of 3.01 mW cm −2 as well as outstanding cycling stability of 417 cycles. This research provides fresh perspectives for designing advanced cathodic electrocatalysts for rechargeable Zn–CO 2 batteries with high‐efficient electricity output together with CO 2 utilization.